Yard and Garden: Onions and Garlic

Harvesting vegetables at the right stage of maturity results in high quality, nutritious products. If properly harvested and stored, onions and garlic will keep most of their original flavor and food value for months. Iowa State University Extension specialists describe the correct harvesting and storage for these two vegetables. To have additional questions answered, contact the experts at hortline@iastate.edu or call 515-294-3108.

When should you harvest onions?

Onions should be harvested when most of the tops have fallen over and begun to dry. Carefully pull or dig the bulbs with the tops attached.

What is the proper way to store onions?

After harvesting the onions, dry or cure the onions in a warm, dry, well-ventilated location, such as a shed or garage. Spread out the onions in a single layer on a clean, dry surface. Cure the onions for two to three weeks until the onion tops and necks are thoroughly dry and the outer bulb scales begin to rustle. After the onions are properly cured, cut off the tops about 1 inch above the bulbs. As the onions are topped, discard any that show signs of decay. Use the thick-necked bulbs as soon as possible as they don’t store well. An alternate preparation method is to leave the onion tops untrimmed and braid the dry foliage together.

Place the cured onions in a mesh bag, old nylon stocking, wire basket or crate. It’s important that the storage container allow air to circulate through the onions. Store the onions in a cool, moderately dry location. Storage temperatures should be 32 to 40 degrees Fahrenheit. The relative humidity should be 65 to 70 percent. Possible storage locations include a basement, cellar or garage. Hang the braided onions from a rafter or ceiling. If storing the onions in an unheated garage, move the onions to an alternate storage site before temperatures drop below 32 F.

What is the storage life of onions?

The storage life of onions is determined by the variety and storage conditions. When properly stored, good keepers, such as ‘Copra’ and ‘Stuttgarter,’ can be successfully stored for several months. Poor keepers, such as ‘Walla Walla’ and ‘Sweet Spanish,’ can only be stored for a few weeks. If the storage temperatures are too warm, the onions may sprout. Rotting may be a problem in damp locations. Inspect the stored onions on a regular basis in fall and winter. Discard any that are starting to rot.

When should you harvest garlic?

Harvest garlic when the foliage begins to dry. In Iowa, garlic is usually harvested in August or September. Carefully dig the bulbs with a garden fork or shovel.

How do you store garlic?

After harvesting the garlic, dry the garlic in a warm, dry, well-ventilated location. Place the garlic on an elevated wire screen or slotted tray to promote drying. When the tops have dried, cut off the dry foliage 1 inch above the bulbs. Also, trim off the roots and brush off any loose soil. Place the bulbs in a mesh bag or open crate and store in a cool (32 F to 40 F), dry (65 to 70 percent relative humidity) area. Garlic can be stored for three to six months if properly dried and stored. An alternate way to store garlic is to braid the foliage together immediately after harvest, dry and then hang the braided garlic in a cool, dry location.